1. Field of the Invention
The present invention is related to a rotor device capable of forcing heat dissipation and particularly to a device to force heat generated during the rotor rotating.
2. Brief Description of the Related Art
Referring to FIG. 1, a conventional rotor assembly of a fan motor includes a fan frame 11 and a hub 12. The fan frame 11 provides a support base 111 with a collar bush 112. A bearing 113 is received in the collar bush 112 and a stator 13 is disposed to surround and fit with the collar bush 112 such that the stator 13 can be attached to the support base 111. The hub 12 has main wall and a circumferential wall such that a space can be defined to receive a shield member 14. The shield member 14 also has a main wall and a circumferential wall to define a space for receive a rotor 15. A plurality of fan blades 121 are radially disposed outside the hub 12 and a spindle 16 is joined to the hub 12 and the shield member 14 at an end thereof and passes through the bearing 113 to allow the hub 12 and the shield member 14 being movably attached to the support base 111.
When the stator 13 and the rotor 15 of the fan motor are magnetized to drive the hub 12 and the shield member 14 rotating due to change of phase, the fan blades thus rotates to move fluid and performs heat dissipation to the hot objects. However, the problem of conventional rotor assembly resides in that heat can be generated from running of the stator 13 and the rotor 15 and most of the heat stays in the hub without removing because of the shield member being enclosed in the hub with poor heat transfer. In this way, a great deal of heat stays in the hub to lead shortened life span of the motor and to increase heat in the system.
Further, US Publication No. 2004/0075356 entitled FAN ROTOR includes a tubular hub having a closed-end wall and an inner wall, with a metal ring receiving in the tubular hub in engagement with the inner wall. The metal ring has a magnet ring embedded therein. Furthermore, the tubular hub is provided with a plurality of retainers for releasably holding the metal ring in the tubular hub.
The problem of the preceding prior art is in that fluid in the hub flows in a swirl way during the hub rotating and the flowing path of the fluid is inconsistent with orientations of the through holes such that fluid inside the hub is not easy to flow outward via the through holes and low convection efficiency is obtained with ineffective heat dissipation.